Reference may be had to the following patents which were developed in a preliminary novelty search and which disclose art having a bearing on the present invention:
U.s. pat. No. 2,138,084 PA0 U.s. pat. No. 2,148,318 PA0 U.s. pat. No. 2,194,902 PA0 U.s. pat. No. 2,355,794